Sweep locks and tilt latches for window sash that open and close vertically and tilt from a vertical plane
xe2x80x9cSweep lockxe2x80x9d is the common name of a cam lock mounted on an upper rail of a lower sash to lock the lower sash to a fixed or movable upper sash in a window. Sweep locks can be used in pairs spaced toward the sides of window sash to interlock the check rails of a pair of closed sash. When locked, sweep locks prevent either sash from moving toward an open position and also strengthen the wind resistance of the closed sash.
xe2x80x9cTilt latchxe2x80x9d is the common name of a latch that keeps a tiltable sash in an upright position for traveling vertically between open and closed positions within a window jamb. Ordinarily, a pair of tilt latches are arranged at stile edges of a lower sash to latch into vertical slots in a window jamb where the tilt latches prevent a lower sash from tilting until the tilt latches are manually unlocked.
Since sweep locks and tilt latches are both mounted on an upper rail of a lower sash, there have been several suggestions in the patent literature that these devices be combined. See for example U.S. Pat. Nos. 1,120,186; 5,090,750; 5,244,238; 5,398,447; and 5,791,700. All these suggestions suffer from disadvantages such as expense, inconvenience, and cumbersome actuation. Some of them also cause simultaneous actuation of sweep locks and tilt latches in undesirable ways. In contrast to these drawbacks, the present invention aims at a low cost, convenient, and functionally desirable interaction of sweep locks and tilt latches.
The invention achieves this improvement by mounting a corresponding pair of sweep locks and tilt latches adjacent each other so that each sweep lock and each tilt latch are manually movable. The sweep locks are arranged to block unlatching movement of the tilt latches, though, whenever the sweep locks are locked. Also, locking the sweep locks moves unlatched tilt latches into latched positions. The only time tilt latches can be unlatched is when corresponding sweep locks are unlocked.
This arrangement assures that tilt latches are latched whenever sweep locks are locked so that the window enjoys maximum possible strength whenever sweep locks are locked. It also requires that the sweep locks be unlocked before tilt latches can be unlatched so that no one attempts to tilt a sash that is held in place with a sweep lock. Since sweep locks are used for locking windows for security and wind-resistance purposes, such an arrangement assures that tilt latches are also latched for the same purposes, whenever the sweep locks are locked. The arrangement also prevents accidental unlatching of tilt latches whenever sweep locks are locked. In normal practice, sweep locks are used more frequently than tilt latches, which are unlatched for tilting a sash inward for washing or repair. The more frequently used sweep locks then ensure that tilt latches remain latched until tilting of a sash is desired, and sweep locks are also unlocked for this purpose.